Exosomes derived from human umbilical cord mesenchymal stem cells promote osteogenesis through the AKT signaling pathway in postmenopausal osteoporosis.

Postmenopausal osteoporosis (PMO) is a relatively common disease characterized by low bone mass and microstructural changes of trabecular bone. The reduced bone strength is caused a variety of complications, including fragility fracture and sarcopenia. We used CCK-8 and EdU assays to evaluate cell proliferation rates. The osteogenesis effect was detected using ALP staining, alizarin red staining, and q-PCR. In vivo, the effects of exosomes derived from HUC-MSCs were evaluated using HE staining, IHC staining and Masson staining. In addition, we explored the mechanism of exosomes and found that the AKT signaling pathway played an important role in osteogenesis and cell proliferation. This paper mainly explored the function of exosomes derived from human umbilical cord mesenchymal stem cells (HUC-MSCs) and provided a new strategy for the treatment of postmenopausal osteoporosis. In conclusion, exogenous administration of exosomes can contribute to the treatment postmenopausal osteoporosis to a certain extent.

Colorimetric recognition of pazufloxacin mesilate based on the aggregation of gold nanoparticles.

A novel colorimetric nanomaterial-assisted optical sensor for pazufloxacin mesilate was proposed for the first time. Pazufloxacin mesilate could induce the aggregation of glucose-reduced gold nanoparticles (AuNPs) through hydrogen-bonding interaction and electrostatic attraction, leading to the changes in color and absorption spectra of AuNPs. The effect of different factors such as pH, the amount of AuNPs, reaction time and reaction temperature was inspected. Under the optimum condition, UV-vis spectra showed that the absorption ratio (A670/A532) was linear with the concentration of pazufloxacin mesilate in the range from 9×10(-8) mol L(-1) to 7×10(-7) mol L(-1) with a linear coefficient of 0.9951. This method can be applied to detecting pazufloxacin mesilate with an ultralow detection limit of 7.92×10(-9) mol L(-1) without any complicated instruments. Through inspecting other analytes and ions, the anti-interference performance of AuNP detection system for pazufloxacin mesilate was excellent. For its high efficiency, rapid response rate as well as wide linear range, it had been successfully used to the analysis of pazufloxacin mesilate in human urine quantificationally.

Applications of magnetic surface imprinted materials for solid phase extraction of levofloxacin in serum samples.

In this work, molecularly imprinted magnetic carbon nanotubes (MCNTs@MIPs) was prepared with surface imprinting technique for extraction of levofloxacin in serum samples. The preparation of molecularly imprinted polymers (MIPs) used levofloxacin as template, methacrylic acid as functional monomer, and ethylene glycol dimethacrylate as cross-linker, and the magnetic carbon nanotubes (MCNTs) was synthesized by solvothermal method. The prepared polymers not only can be separated and collected easily by an external magnetic, but also exhibited high specific surface area and high selectivity to template molecules. Kinetic adsorption and static adsorption capacity investigations indicated that the synthesized MCNTs@MIPs had excellent recognition towards levofloxacin. Furthermore, magnetic solid phase extraction (MSPE) using the prepared MCNTs@MIPs as sorbent was then investigated, and an efficient sample cleanup was obtained with recoveries ranged from 78.7 ± 4.8 % to 83.4 ± 4.1%. In addition, several parameters, including the pH of samples, the amount of MCNTs@MIPs, the adsorption and desorption times, and the eluent, were investigated to obtain optimal extraction efficiency. Under the optimal extraction conditions, the stability of the polymer was also evaluated, and the average recovery reduced less than 7.6% after 5 cycles. MCNTs@MIPs successfully applied in the preconcentration and determination of levofloxacin in serum sample suggested that the MSPE method based on the novel polymers could be a promising alternative for selective and efficient extraction of trace amounts of pharmaceutical substances in bio-matrix samples.

Functional degeneration in dorsal and ventral attention systems in amnestic mild cognitive impairment and Alzheimer's disease: an fMRI study.

Attention deficits in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) have already been previously proposed. However, previous studies lacked systematic comparisons on multiple phases of disease progression. In this work, we compared spontaneous functional connectivity in dorsal and ventral attention networks (DAN, VAN) in patients with aMCI and AD. Additionally, we performed a behavioral test-attention network test (ANT) which examined three attention performances: alerting, orienting, and executive control. One-way analysis of variance revealed significant group-differed functional connectivity in both networks. Specifically, functional connectivity with the dorsal seed differed in left lateralized fronto-parietal area and medial dorsal frontal cortex and posterior cingulate cortex, whereas functional connectivity with the ventral seed differed in right ventral and dorsal frontal cortex. For patients with AD, both attention networks showed decreased functional connectivity in regions of interest comparisons. Accordingly, the behavioral results showed bad performance in three attention functions. These findings suggested impaired functional anatomy for top-down and bottom-up processing in AD patients. Whereas for patients with aMCI, attention systems degenerated in a selective way, specifically, with decreased functional connectivity in DAN, but preserved or enhanced one in VAN. Additionally, patients with aMCI showed selective attention deficits with preserved alerting and orienting performance but impaired executive control performance, suggesting an impaired functional anatomy for top-down processing, while preserved functional architecture for bottom-up performance. The findings indicated that diverse extent and onset of functional degenerations in dorsal and ventral attention systems as the disease severity progressed. This might provide more evidence to distinguish aMCI which would easily progress to AD.